United States Department of Agriculture

Marketing and Regulatory Programs

 Animal and Plant Health Inspection Service

 Veterinary Services

 VS Guidance 13416.1

1

Requirements for Spayed Heifers from Mexico

1. Purpose and Background

This document defines the requirements for importing spayed heifer cattle from Mexico and 

provides guidance for Veterinary Services (VS) personnel overseeing and monitoring the 

importation of spayed heifers.

Import requirements for Mexican spayed heifers were developed in 2005 to prevent the 

introduction of brucellosis-infected female feeder cattle. As a result, VS requires all Mexican 

female feeder cattle presented for importation be spayed and determined not pregnant at 

the time of spaying. Such cattle are referred to hereinafter as “spayed heifers.” The 

requirements are contained in title 9, Code of Federal Regulations (9 CFR) 93.400 et. seq. 

and in a protocol negotiated directly with Mexico (Protocolo de Castracion de Vaquillas Para 

La Exportacion, hereinafter “the protocol”).

Animal and Plant Health Inspection Service (APHIS) and Secretaria de Agricultura, y

Desarrollo Rural (Ministry of Agriculture, Rural Development – SADER), Servicio Nacional 

de Sanidad, Inocuidad y Calidad Agroalimentaria (National Service of Health, Safety and 

Quality Agrofood – SENASICA) authorities will work together to implement the activities set 

forth in this guidance document.

This guidance document represents the Agency’s position on this topic. It does not create or 

confer any rights for or on any person and does not bind the U.S. Department of Agriculture

(USDA) or the public. The information it contains may be made available to the public. While 

this document provides guidance for users outside VS, VS employees may not deviate from 

the directions provided herein without appropriate justification and supervisory concurrence.

2. Document Status

A. Review date: 07/23/2022.

B. This document replaces VS Memorandum No 591.63, which is cancelled. The content of 

the document has been updated to reflect requirement changes negotiated with Mexico, 

and also to reflect changes to VS structure after its 2018 reorganization.

3. Reason for Reissuance 

Not applicable.
 United States Department of Agriculture

Marketing and Regulatory Programs

 Animal and Plant Health Inspection Service

 Veterinary Services

 VS Guidance 13416.1

2

4. Authority and References

A. Authorities (Code of Federal Regulations (CFR) and U.S. Code (U.S.C.)):

• 7 CFR 371.4

• 9 CFR 93.427

B. Documents:

VS Bulletin 2018.03: Bovine Tuberculosis Testing Requirements for Cattle Imported to 

the United States from Mexico

5. Audience

VS employees, other Federal and State agencies, and members of the public.

6. Guidance

A. Eligibility for Spaying in Mexico

1) Under the terms of Mexico’s import protocol with the United States, heifers presented 

for spaying in Mexico for export to the United States must have been born and 

continuously resided in Mexico. In addition, the heifers must be under 18 months of 

age at the time of surgery, as confirmed by dental examination to be performed by 

the veterinary surgeon performing the surgery.

2) A veterinary surgeon approved by SADER must perform the spaying; see Section 

C.1).

3) Holstein and Holstein-cross spayed heifers are ineligible for export to the United 

States.

B. APHIS Import Requirements for Spayed Heifers

1) Identification

a. Spayed heifers must have an official National Individual Livestock Identification 

(Sistema Nacional de Identificacion Individual de Ganado) System (SINIIGA) ear

tag.

b. Spayed heifers must be identified with a distinct, permanent "M" mark (e.g, 

brand) that is legible and placed on the right side of the tailhead. New branding 

guidelines for Mexican spayed heifers require the “M” brand to be between 3 

inches and 5 inches (7.5 and 12.5 cm) in size, and located on the right side of the 

animal within 4 inches (10 cm) of the midline of the tailhead (this should be 

interpreted as the top of the brand being within 4 inches from and above the hook 

and pin bones). The brand should be within 18 inches (45.7 cm) of the anus.
 United States Department of Agriculture

Marketing and Regulatory Programs

 Animal and Plant Health Inspection Service

 Veterinary Services

 VS Guidance 13416.1

3

Additionally the “M” points may be rounded as opposed to having sharp corners 

for ease of application. See Attachment 2, Breeding Cattle branding diagram.

c. APHIS also requires a blue metal Mexican export eartag, in accordance with

9 CFR 93.427(d).

2) Documentation

a. As set forth in the protocol, a spay certificate (see Attachment 1) or photocopy as 

described in the next subsection must accompany spayed heifers presented for 

entry to the United States.

b. The following applies to a group/lot of spayed heifers listed on one spay 

certificate, but divided into two or more lots for presentation at the VS port of 

entry on different days: If the original spay certificate is not available for the 

second or subsequent lots, photocopies of the certificate will be allowed if the 

copies are countersigned and sealed by a SADER veterinarian.

3) Other Requirements

a. Spayed heifers must comply with the tuberculosis (TB), fever tick, and other 

requirements in 9 CFR 93.427 and VS Bulletin 2018.03; "Bovine Tuberculosis 

Testing Requirements for Cattle Imported to the United States from Mexico."

b. Under the terms of the protocol, spayed heifers must be presented for entry into 

the United States no sooner than 21 days and no later than 180 days from the 

date of surgery (i.e., must be less than 24 months of age when they enter the 

United States). Cattle that have the middle two incisors erupted and fully 

developed are considered 24 months of age.

c. Surgical wounds must be completely healed when the heifers are presented at 

the port.

d. The protocol with Mexico requires that pre-export testing in Mexico be performed

either before spay surgery, or no sooner than 60 days after spay surgery. For 

example, an animal could be injected with tuberculin 72 hours before the 

scheduled spay surgery and the TB test read no later than the day of surgery. 

Alternatively, a TB test may be conducted at least 60 days past the surgery date 

to avoid the possibility that the stress of the surgery would interfere with the TB 

test results.

Note: APHIS will not accept TB tests performed in Mexico within 60 days 

following the spay surgery date. If two TB tests are conducted, they must be 

conducted at least 60 days apart. 
 United States Department of Agriculture

Marketing and Regulatory Programs

 Animal and Plant Health Inspection Service

 Veterinary Services

 VS Guidance 13416.1

4

C. Roles and Responsibilities

1) Mexico

a. The protocol makes SADER responsible for approving the training of veterinary 

surgeons and overseeing/auditing the supervising veterinarians in the proper 

techniques for spaying heifers in Mexico.

1. Approved veterinary surgeons are veterinarians who have received 

training sanctioned by SADER, are included in the SADER list of 

veterinarians approved to perform spay surgeries, will spay according to the 

approved protocol, and are authorized by SADER to issue spay certificates.

2. Approved supervising veterinarians are Committee, State, or Federal 

veterinarians who have received proper training endorsed by SADER, are 

included in the SADER list of veterinarians approved to supervise spay 

surgeries, will supervise all spay surgeries and ensure surgeries are 

performed properly, and ensure spay heifers are properly branded and 

tagged. This person will endorse spay certificates.

b. SADER will provide a designated point of contact to LAIE who will keep an 

official list of SADER-approved veterinary surgeons authorized to perform 

spaying, and a list of the approved supervising veterinarians who will observe all 

surgeries and endorse the spay certificates. SADER will update the list at least 

annually. SADER will update the list more often if it adds or deletes approved 

veterinary surgeons. SADER will then resubmit the list to the LAIE point of 

contact. These lists will be posted on the LAIE SharePoint site and on the 

SADER/SENASICA web page. For further information on the 

SADER/SENASICA’s web page, please contact the Southern Border Port 

Director or the LAIE Ruminant Import Staff listed on the last page of this 

document.

The SADER-approved supervising veterinarian (in most cases a Committee

veterinarian; however, State or Federal veterinarians can also perform these 

duties) authorized to monitor the spaying procedures must be continually present 

during 100 percent of the surgeries performed.

c. The approved supervising veterinarian can monitor up to three veterinary 

surgeons performing spay surgeries simultaneously, at the same location, in a 

given day.

d. The approved supervising veterinarian will observe the size and location of 

brands and placement of ear tags for spayed heifers and record the ear tag

numbers on the spay certificate.
 United States Department of Agriculture

Marketing and Regulatory Programs

 Animal and Plant Health Inspection Service

 Veterinary Services

 VS Guidance 13416.1

5

e. The approved veterinary surgeon may perform a maximum of 300 spay surgeries 

in a 24-hour period.

f. All heifers are required to have a SINIIGA ear tag. When heifers do not have a 

SINIIGA ear tag at the time of surgery, the approved veterinary surgeon must 

place a SINIIGA ear tag to each animal (without a tag) immediately after surgery.

g. The veterinarians SADER approves to perform and/or supervise spay 

procedures for exported heifers must certify that all pertinent required 

documentation has been verified and found acceptable before signing. Under the 

protocol, the official Original Spay Certificates and other certificates required for 

exportation to the United States must be kept on file for at least 3 years by both 

the issuing (approved surgeon) veterinarian and the SADER-approved 

supervising veterinarian. These documents must be available for review on 

APHIS’ request.

h. SADER/SENASICA will audit the supervising process to verify that Mexican 

States are implementing the spay heifer program properly.

2) United States

a. LAIE will maintain the list of Mexican supervising veterinarians and veterinary 

surgeons (as received from SADER) on the APHIS VS Strategy and Policy LAIE 

SharePoint site. The list will include the dates the supervising veterinarians and 

veterinary surgeons were trained in their duties associated with the Mexican 

Spayed Heifer Program.

b. The Southern Border Port Director will periodically review the border States’ 

activities to assist APHIS port veterinarians with implementation issues and to 

monitor APHIS personnel for compliance with this document’s provisions. In 

addition, the Southern Border Port Director will serve as a liaison between border 

State personnel and LAIE, and will report noncompliance issues to the LAIE 

Ruminant Import staff.

c. APHIS port veterinarians will inspect spayed heifers at the port of entry and verify 

the following:

1. The Mexican veterinarians listed on the spay certificate are authorized to 

issue or endorse the document.

2. The required types of identification and documentation listed in part B. 1)

accompany the animals, and the ear tags correlate with each other and other 

documentation.

3. Age, TB testing timelines, wound healing, and other import eligibility factors 

listed in part B. 3) are acceptable.
 United States Department of Agriculture

Marketing and Regulatory Programs

 Animal and Plant Health Inspection Service

 Veterinary Services

 VS Guidance 13416.1

6

4. In cases of questionable spaying or to determine the pregnancy status of 

individual animals, rectal palpation may be performed at the discretion of 

APHIS port veterinarians to evaluate the animal’s status. 

5. Animals not listed on spay certificates or otherwise not meeting all APHIS 

entry requirements, will be refused entry and returned to Mexico. APHIS port 

veterinarians will also monitor consignments for compliance as detailed in 

part D and keep records (notes made in the Veterinary Services Process 

Streamlining database regarding reasons for rejection, and notifications sent 

to LAIE when applicable) of monitoring activities.

d. Heifers that do not meet the above standards will be permanently branded with 

“CN” for “Consumo Nacional” by a SADER official or other person designated by 

port inspection facility management to render the animal ineligible for entry into 

the United States. The application of the branding must be observed by APHIS 

personnel before removing the animals from the port.

D. Compliance

1) APHIS personnel will inspect ear tags using the guidelines set forth below:

a. For lots of up to 30 spayed heifers, inspect every ear tag to verify a match with 

the accompanying spay certificate. If there are any non-matches, the individual 

animal (or animals) or the entire lot may be rejected at the discretion of the 

inspector.

b. For lots between 31 to 100 heifers, inspect every third tag to verify a match with 

the accompanying spay certificate. If there are any non-matches, inspect and 

verify all remaining tags. Individual non-matching animals or the entire lot may be 

rejected at the discretion of the inspector.

c. For lots of more than100 heifers, inspect every third tag for the first 100 heifers, 

and every tenth tag after that, to verify a match with the accompanying spay 

certificate. If there are any non-matches, inspect and verify all remaining 

tags. Individual non-matching animals or the entire lot may be rejected at the 

discretion of the inspector.

2) The port veterinarian has the discretion to visually inspect a heifer’s dentition. The

port veterinarian may further determine compliance by random checks through rectal 

palpation or other appropriate means to detect pregnancy, the presence of ovaries, 

or other indications of improper technique in the spaying process.

3) APHIS may reject single animals or the entire lot of spayed heifers presented for 

importation to the United States on the detection of compliance issues through 

monitoring as stated above. 
 United States Department of Agriculture

Marketing and Regulatory Programs

 Animal and Plant Health Inspection Service

 Veterinary Services

 VS Guidance 13416.1

7

4) If a Mexico veterinary surgeon (or supervising veterinarian) is determined to be 

responsible for incidents of noncompliance regarding the spaying of heifers, 

depending on the severity of the noncompliance the veterinarian could be 

temporarily or permanently removed from the list of approved veterinarians, and any 

additional lots spayed or certified by the veterinarian will not be considered eligible 

for entry to the United States.

5) Any reports of improper spaying should be communicated to the Southern Border 

Port Director, who will contact LAIE Ruminant Import staff via email, with the subject 

“Improper Spaying of Mexican Heifers”, at

VS.Live.Animal.Import.Export@aphis.usda.gov.

6) APHIS will actively pursue any reports of female feeder cattle aborting or calving in 

feedlots or pastures, as well as Food Safety and Inspection Service slaughter reports 

of pregnant animals or animals with ovaries. To notify the LAIE Ruminant Import staff 

immediately of any such incidents, use the email address and subject header above. 

7) LAIE staff will periodically analyze all reports of noncompliance. Multiple shipments 

of animals from Mexico found to be improperly spayed, or misidentified as nonpregnant, may result in a number of possible consequences, including re-evaluation, 

suspension, or termination of the program.

7. Inquiries

To contact the Southern Border Ports supervisory veterinary medical officer, call the office at 

(512) 383-2400. For questions regarding this document, contact the LAIE Ruminant Import 

staff at VS.Live.Animal.Import.Export@aphis.usda.gov or 301-851-3300 Menu Option # 2.

Attachment 1: Spay Certificate

Attachment 2: Feeder (Spayed) Cattle branding diagram
FECHA DE CASTRACIÓN

CLAVE : VIGENCIA :

No No No

1 30 53

2 31 54

3 32 55

4 33 56

5 34 57

6 35 58

7 36 59

8 37 60

9 38 61

10 39 62

11 40 63

12 41 64

13 42 65

14 43 66

15 44 67

16 45 68

17 46 69

18 47 70

19 48 71

20 49 72

21 50 73

22 51 74

23 52 75

24

25

26

27

28

29

VIGENCIA :

VALID TO:

NUMERO DE ARETE 

OFICIAL

RANCHO EN EL CUAL LAS VAQUILLAS FUERON CASTRADAS :

REPORTE DE CASTRACION DE VAQUILLAS

BOVINE FEMALE CASTRATION REPORT

FOLIO No.:

PAGE OF

HOJA DE

RANCH ON WICH BOVINE FEMALE WERE CASTRATED :

Note the earring number if animals have already been approved for export; if not, draw a line through the column.

OFICIAL FEDERAL DE MÉXICO EN SALUD ANIMAL QUE ENDOSA ESTE CERTIFICADO

FIRMA:

SIGNATURE:

FIRMA:

EXPORT EARTAG NUMBER OFICIAL EARTAG NUMBER

Nombre / Name

Firma / Signature

SIGNATURE:

NUMERO DE ARETE DE 

EXPORTACIÓN

NUMERO DE ARETE 

OFICIAL

NUMERO DE ARETE DE 

EXPORTACIÓN

Anote el numero de arete si el animal ya ha recibido aprovación para ser exportado, si no trace una linea a lo largo en la columna.

CODE:

NUMERO DE ARETE DE 

EXPORTACIÓN

NUMERO DE ARETE 

OFICIAL

EXPORT EARTAG NUMBER OFICIAL EARTAG NUMBER

CODE:

CLAVE :

VALID TO:

EXPORT EARTAG NUMBER OFICIAL EARTAG NUMBER

(180 DIAS/DAYS)

VETERINARIO CIRUJANO SUPERVISOR AUTORIZADO

NOMBRE :

NAME :

NOMBRE

NAME

N° DE ANIMALES CASTRADOS :

N° OF CASTRATED HEADS:

VETERINARIO CIRUJANO AUTORIZADO

OWNER OF BATCH OF ANIMALS CASTRATED :

DUEÑO DE LOS ANIMALES CASTRADOS :

MUNICIPIO :

AUTORIZED VETERINARY SURGEON 

ESTADO :

MUNICIPALITY : STATE :

NO EXPORTARSE ANTES DE: (21 DIAS/DAYS)

DO NOT EXPORT BEFORE: NO EXPORTARSE DESPUES 

AUTORIZED SUPERVISING VETERINARY SURGEON

CCP.COMITE CCP.SENASICA CCP.CIRUJANO CCP.SUPERVISOR

DE

DATE OF CASTRATION MM (MONTH) AAAA (YEAR)

DE

DD (DAY)

DIRECCION DEL RANCHO DONDE LAS VAQUILLAS FUERON CASTRADAS:

ADDRESS OF RANCH WHERE BOVINE FEMALES WHERE CASTRATED :

MEXICAN FEDERAL ANIMAL HEALT OFFICIAL ENDORSING THE CERTIFICATE
No No No

76 122 162

77 123 163

78 124 164

79 125 165

80 126 166

81 127 167

82 128 168

83 129 169

84 130 170

85 131 171

86 132 172

87 133 173

88 134 174

89 135 175

90 136 176

91 137 177

92 138 178

93 139 179

94 140 180

95 141 181

96 142 182

97 143 183

98 144 184

99 145 185

100 146 186

101 147 187

102 148 188

103 149 189

104 150 190

105 151 191

106 152 192

107 153 193

108 154 194

109 155 195

110 156 196

111 157 197

112 158 198

113 159 199

114 160 200

115 161 201

116

117

118

119

120

121

REPORTE DE CASTRACION DE VAQUILLAS

BOVINE FEMALE CASTRATION REPORT

FOLIO No.:

HOJA DE

PAGE OF

OFICIAL EARTAG NUMBER

NUMERO DE ARETE DE 

EXPORTACIÓN

NUMERO DE ARETE 

OFICIAL

NUMERO DE ARETE DE 

EXPORTACIÓN

NUMERO DE ARETE 

OFICIAL

NUMERO DE ARETE DE 

EXPORTACIÓN

NUMERO DE ARETE 

OFICIAL

EXPORT EARTAG NUMBER OFICIAL EARTAG NUMBER EXPORT EARTAG NUMBER OFICIAL EARTAG NUMBER EXPORT EARTAG NUMBER

OFICIAL FEDERAL DE MÉXICO EN SALUD ANIMAL QUE ENDOSA ESTE CERTIFICADO

MEXICAN FEDERAL ANIMAL HEALT OFFICIAL ENDORSING THE CERTIFICATE

Nombre / Name

Firma / Signature

Anote el numero de arete si el animal ya ha recibido aprovación para ser exportado, si no trace una linea a lo largo en la columna.

Note the earring number if animals have already been approved for export; if not, draw a line through the column.

CCP.COMITE CCP.SENASICA CCP.CIRUJANO CCP.SUPERVISOR
No No No

202 248 289

203 249 290

204 250 291

205 251 292

206 252 293

207 253 294

208 254 295

209 255 296

210 256 297

211 257 298

212 258 299

213 259 300

214 260

215 261

216 262

217 263

218 264

219 265

220 266

221 267

222 268

223 269

224 270

225 271

226 272

227 273

228 274

229 275

230 276

231 277

232 278

233 279

234 280

235 281

236 282

237 283

238 284

239 285

240 286

241 287

242 288

243

244

245

246

247

NUMERO DE ARETE DE 

EXPORTACIÓN

CCP.COMITE CCP.SENASICA CCP.CIRUJANO CCP.SUPERVISOR

Firma / Signature

Anote el numero de arete si el animal ya ha recibido aprovación para ser exportado, si no trace una linea a lo largo en la columna.

Note the earring number if animals have already been approved for export; if not, draw a line through the column.

NUMERO DE ARETE OFICIAL NUMERO DE ARETE DE 

EXPORTACIÓN

NUMERO DE ARETE OFICIAL NUMERO DE ARETE DE 

EXPORTACIÓN

NUMERO DE ARETE OFICIAL

Nombre / Name

REPORTE DE CASTRACION DE VAQUILLAS

BOVINE FEMALE CASTRATION REPORT

FOLIO No.:

HOJA DE

PAGE OF

MEXICAN FEDERAL ANIMAL HEALT OFFICIAL ENDORSING THE CERTIFICATE

OFICIAL FEDERAL DE MÉXICO EN SALUD ANIMAL QUE ENDOSA ESTE CERTIFICADO

EXPORT EARTAG NUMBER OFICIAL EARTAG NUMBER EXPORT EARTAG NUMBER OFICIAL EARTAG NUMBER EXPORT EARTAG NUMBER OFICIAL EARTAG NUMBER
 United States Department of Agriculture

Marketing and Regulatory Programs

 Animal and Plant Health Inspection Service

 Veterinary Services

 VS Guidance 13416.1

8

Attachment 2: Feeder (Spayed) Cattle Branding Diagrams